The purpose is to determine the sensitivity of various acoustic measures to vocal patholgy associated with laryngeal disease/disorders including laryngeal carcinoma, vocal polyps, vocal nodules and contact ulcers. Acoustic assessment procedures will provide an objective means of quantifying voice disorders of dysfunctions, and evaluating the effects of various treatments on vocal pathologies. A microprocessor has been developed for quantifying frequency perturbation (jitter) while a similar system has been developed for quantifying amplitude perturbation (shimmer). Both measurement techniques have 6-10 times improved resolution over previous methods of measurement, and provide indices of vocal function which are stabe across normal adults with different fundamental frequencies.